explore the idea of electric fields. The easiest way to think about electric fie
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Question
explore the idea of electric fields. The easiest way to think about electric fields is that the field shows the force felt by a positive charge if placed at a location.
Explore the simulation at HYPERLINK "https://phet.colorado.edu/sims/html/charges-and-fields/latest/charges-and-fields_en.html"https://phet.colorado.edu/sims/html/charges-and-fields/latest/charges-and-fields_en.html. You can put positive and negative charges on the working area. You can put multiple charges on top of one another to “change” the amount of charge. It gives you the direction of the electric field; the strength is shown by the brightness of the arrow. The yellow sensor will show you the electric field strength and direction at the place you put it. Answer the following questions on your whiteboard.
What direction is the electric field around a positive charge? Is this consistent with the definition above? Explain.
What direction is the electric field around a negative charge? Is this consistent with the definition? Explain.
If you put a positive and negative charge on the same line, what is the field like in between them? How is this consistent with the definition?
What variables affect the electric field? (What can you do to change the electric field?) You should be able to come up with two variables.
Can you set up multiple charges so that at some point on the screen the electric field becomes zero? (Can you make one of the arrows disappear entirely?)
Now that you have an idea about fields, see if you can win the electric field hockey game at HYPERLINK "https://phet.colorado.edu/en/simulation/legacy/electric-hockey" https://phet.colorado.edu/en/simulation/legacy/electric-hockey!(Level 3 is very hard, but it has been done!)
Part Two: Lab experiment
How good is this simulation? We are going to test this by using simulation data to calculate the value of k.
The equation for the electric field due to a point charge is
E = |kq/r2|
where E is the field strength, q is the size of the charge, and r is the distance away from the charge. Like the force equation, it is the absolute value of the resulting number, because it only gives you the size of the field, not the direction.
What do you need to measure in order to calculate the value of k?
Set up a table in Excel that does what you need it to.
Using the simulation’s measuring tools, take at least 15 points of data, using both negative and positive charges. Here is the procedure to get you started:
Click off the “Electric Field”. Click on “Values” and “Grid”.
Place one charge anywhere on the screen.
Place the sensor somewhere on the screen. This gives you the electric field value at that point in units of (V/m).
Use the tape measure to determine the distance between the charge and the sensor.
Determine your value of k. To find the absolute value in Excel, use =ABS(otherstuffhere).
Calculate the percent error in your value.
% error = [(actual – experimental)/actual]*100
Your results should include your value for k and your decision on if the simulator is using a good value for k.
Standard lab report for today. You can probably guess that any errors are not in the simulation’s value for k!
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Explanation / Answer
Electric field is a vector quantity whose direction is such that a positive test charge would be pushed when placed in the field. Thus, the electric field direction about a positive charge is always directed away from the charge.
In the same manner, the electric field for a negative charge is always directed towards the charge itself.
If we.put a positive and a negative charge on same line then electric field vectors will go out from positive to negative charge. The direction will be from positive to negative charge.
Two variables which affect electric field are amount of charge that produces the field and distance from charge.
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